8 1/2 week old roo started crowing

I ordered one RIR roo with my batch and ended up with two RIR roos and one EE roo. I had just finished the morning duties and closed the coop door. Then I heard this very strange and comical sound coming from the coop. I immediately opened the door and the EE roo was standing by the door by himself. All the other chickens were frozen against the far wall. They appeared to be startled and saying the same thing I was. "What the heck was that"?

The chicks in my ginormous brooder are a mix of breeds, LF and bantam, and "straight run" as I hatched them. At 3 weeks, one of the Cochins started to crow. They're now 9 weeks old and he is the most mature of them all and obviously the Boss of The Brooder. Getting pretty good at crowing, too!